Guide rail and link chain for chain saw

ABSTRACT

On two opposite long narrow sides of a guide rail (1) of a chain saw for stone are arranged slide rails (3) of plastic. The slide rails (3) are located between the side walls (18, 19) of the guide rail. A link chain (2) consists of slide elements (6) and pairs of side guide members (7, 8) which are joined with each other through links (5). The slide elements (6) lie, on one side, on a surface (15) of the slide rail (3) and have, on the opposite side, cutting plates (4). In the slide rail (3) are arranged central coolant channels (13) which are connected with the coolant feed present in the core of the guide rail (1). The side guiding of the chain (2) is assured through the side guide members (7, 8) lying against the side surfaces (11, 12) of the slide rail (3).

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to a guide rail and link chain for a chain sawused for finishing work on concrete, stone and masonry and in particularto a guide rail having coolant channels.

2. Description of the Prior Art

One such link chain for a chain saw is known from the German PublicationDE No. 3,332,051 A1. Here, the guide rail, also called the "sword", isprovided on the lengthwise side with additional rails of metal. Theguide rail is designed hollow. The hollow space serves as a channel forcoolant, and on the side surfaces of the additional rails, coolantchannels are arranged. The respective link chain consists of rollers,supported on pegs which are joined with each other by guide andconnecting members. The rollers run on the outer surfaces of theadditional rails, and the chain is turned, at the front end of the guiderail, over a chain wheel. The guide members of the chain are fastened tothe cutting plates set with diamonds, which serve as cutting tools.

Although the chain can be constantly fed through the guide rail withcoolant and lubricant, such guide rail and link chain systems have highwear and a short life. The dust from the cutting plates and that fromthe cut, settle on the additional rails, the guide members and therollers which wears these metal parts away to the point of destruction.The cutting dust also penetrates between all the sliding surfaces, andthe allowable clearance between the parts is very quickly exceededthrough wear. Since such chains are very expensive, they cannot beeconomically used because of the rapid wear. The frequent replacement ofchains necessary, and the interruption of operation cause high operationcosts also.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a guide rail and linkchain system, which has a long useful life, in which the wear betweenthe chain members and the guide members is low, which has high securityagainst disturbances, and which is simple to produce.

This problem is solved through the features defined in the distinguishedpart of claim 1. Further advantages of the invention are given accordingto the features of the dependent claims.

The guide rail and link chain system according to the invention, has amuch greater life than the known chain saws. This is attained by thefact that the guide rail of the chain saw has on both lengthwise sides,slide rails of plastic, on which metal slide elements of the chainslide. The slide rails are laid into grooves located on the lengthwisesides of the guide rail and are made of plastic material with highresistance to dust of abrasion and to water. Since the coolant channelsextend through the central portion of the slide rails, the cooling andlubricating fluid comes out of the middle of slide surface. In this way,the cutting and grinding dust is rinsed away from the zone of the slidesurface, and between the slide rails and the slide elements of thechain, a fluid film is formed, which prevents wear of the metal chainmembers against the slide rails.

The links in the chain are completely shielded from the outsideenvironment, and grinding and cutting dust cannot penetrate into thelinks. This is assured, on the one hand, by the fact that the slidingsurfaces of the links are covered on all sides, and on the other hand,by lubricant from the center of the link which is consistently pressedover all the sliding surfaces toward the outside. Water-resistantgreases with additives, such as molybdenum and other known additives aresuitable as lubricants. In the contact zone of the sliding surfacesbetween the slide elements and the slide rails, the pressure of thecoolant provides that only slight amounts of lubricant come out of thesliding surfaces between the guide members and the slide elements. Inthis way, the loss of lubricant is slight and the links can berelubricated within the normal interruptions of work. With regularlubrication of the chain and feeding of sufficient coolant through theguide rail, the guide rail and link chain system of the presentinvention reaches lifetimes which are several times greater than in theknown link chains for concrete, stone and masonry. Since the parts ofthe chain consist of flat elements which are not arched or bent, theycan easily be ground exactly to dimensions, by which an economical chaincan be built. Since the cutting plates are fastened to support plates,there is no danger that the hardened chain members will be softened bysoldering. Moreover, the cutting plates with their support plates can beplaced on the chain members at the most favorable point in time for themanufacture, which in turn makes possible a simpler and betterproduction of the chain.

BRIEF DESCRIPTION OF THE DRAWINGS

One example of execution of the invention is explained in detail below,with reference to the drawings, in which

FIG. 1 shows a portion of a guide rail with a link chain for a chainsaw, in side view; and

FIG. 2 shows a cross section through the link chain and the upper partof a guide rail through one link of the link chain.

DESCRIPTION OF A PREFERRED EMBODIMENT

The section represented in FIG. 1 of a guide rail 1, or sword, of achain saw, shows the front side wall 18, an intermediate piece 16 towhich are fastened the side walls to maintain the side walls the propermutual distance apart, and an upper slide rail 3 lying on theintermediate piece 16. The slide rail 3, in the example shown, consistsof Bakelite, that is, a layer-pressed material, and is inserted into thespace between the side walls 18, 19 of the guide rail 1. On the slidingsurface 15 of the slide rail 3 lie the slide elements 6 of the linkchain 2. The slide elements 6 are joined together, through links 5, bymeans of the side guide members 7, 8. To the upper side of the slideelements 6 are fastened cutting plates 4, which are formed from hardenedmetal plates, set with diamonds.

FIG. 2 shows the link chain 2 and the edge of the guide rail 1, inenlarged representation. The section shown passes through one of thelinks 5 and a coolant channel 13 in the slide rail 3. The link 5consists of a bolt 21, which has offset pegs 23, 24 at both ends. Thepegs 23, 24 have a smaller diameter than the intermediate portion of thebolt 21. The bolt 21 is rotatably supported in a bearing bushing 20,which is pressed into the slide element 6. The pegs 23 and 24 are alsosupported in bores in the side guide members 7 and 8, being fixedlyconnected in the known way, with these side guide members 7 and 8. Inthe example shown, this is done by the fact that the outer surfaces ofthe pegs 23 and 24 are deformed into a ring, and in this way, materialis driven outwardly and the bolt 21 is clamped to the side guide members7 and 8. The dimensions between the two side guide members 7 and 8, aswell as the width of the bearing bushing 20 and the slide element 6 areso chosen that the slide elements 6 and the side guide members 7 and 8can be swung, easily and free of play, around the axis 22 in relation toeach other. The side guide members 7 and 8 are also designed so thatthey overlap the side surfaces 11, 12 of the slide rail 3, and in thisway, the link chain 2 is guided sidewise on the slide rail 3 with theleast possible play. The slide elements 6 have on their underside,sliding surfaces 9, which lie on the surfaces 15 of the slide rail 3.Through the intermediate pieces 16 in the guide rail 1, coolant channels17 lead outward from the inner hollow space of the guide rail 1. Fromthese coolant channels 17 lead out, in each case, two coolant channels13, which are arranged in the center of the slide rail 3. The outletopenings of these coolant channels 13 are on the surface 15 of the sliderail 3, in the area of the central axis 14. Thus, the coolant fedthrough the guide rail 1 flows through the coolant channels 17 and 13,and flows outwardly over the surface 15.

In the center of the link 5 is a lubricant channel 25, closed at one endby a plug 30, and has at the other end a ball valve 32 biased by aspring 31. From the central lubricant channel 25 go out one or moreradial bores 26, which form lubricant channels and make possible thefeeding of lubricant to the outer surface 27 of the bolt 21. The ballvalve 22 prevents the penetration of water but makes possible thepressing of water-resistant molybdenum grease into the lubricantchannels 25 and 26. Along the outer surface 27 of the bolt 21, thegrease is pressed outward and also fills the slide surfaces between theslide elements 6 and the side guide members 7 and 8. In this way, thecoolant and the grinding or cutting dust are prevented from penetratingbetween these slide surfaces and damaging them. In the relubrication,any dirt particles which have penetrated in are carried outward, andalso the dirt particles carried by the stream of coolant through thecoolant channels 13 are carried away from these slide surfaces. Theguide rail and link chain system has, in this way, a self-cleaningeffect, and provides constantly for an optimal lubrication and a slidefilm between all sliding surfaces. Since the pegs 23, 24 of the bolt 21are connected, form-fitting, with the side guide members 7 and 8,respectively, the outer surface 27 of the slide surface of the bolt 21is encapsulated toward the outside and protected from dirt.

As can be seen from FIGS. 1 and 2, the cutting plates 4 are fastened tobearing plates 28. The fastening of the cutting plates 4 to the bearingplates 28 normally takes place through hard soldering methods. Thebearing plates 28 cover the entire base surface of the cutting plates 4,by which there is given between the cutting plates 4 and the bearingplates 28 the greatest possible adhesion and contact surface. On theslide elements 6, corresponding openings are provided at the upper end10, while cams 29 grip over the projecting edges of the bearing plates28. The fastening of the bearing plates 28 into the openings or onto thecams 29 of the slide elements 6, takes place by gluing or riveting thecams 29. This fastening process assures a simple and secure fasteningand prevents the hardened slide elements 6 from being made soft againthrough attaching the cutting plates 4 by a soldering process. Accordingto the load on the chain and the kind of use, the bolts 21 and thebearing bushings 20 have a hardness of 55 to 65 Rockwell C, or HRC, andthe slide elements 6 and the side guide members 7 and 8 a hardness of 35to 48 Rockwell C or HRC. As coolant may be used any known cutting andcoolant aid for stone work.

I claim:
 1. Guide rail and link chain for a chain saw for the finishingof concrete, stone and masonry, wherein coolant channels extend throughthe guide rail and cutting plates are connected with chain members ofthe link chain, with the distinction that the guide rail (1) includesplastic slide rails (3) on both lengthwise sides, the chain (2) isguided by and contacts these plastic slide rails (3) only, the chain (2)includes pairs of side guide members (7, 8), and each of the side guidemembers (7, 8) overlaps and lies against a respective outer side surface(11, 12) of the slide rail (3), each pair of side guide members (7, 8)is interconnected through a link (5) and by metal slide elements (6), asliding surface (9) of each slide element (6) is supported by the outersurface (15) of the slide rail (3) and the cutting plates (4) arelocated on a side (10) of the slide element (6) opposite from the guiderail (1).
 2. Guide rail and link chain for chain saw according to claim1 with the distinction that the link (5) includes a bearing bushing (20)pressed into the slide element (6), a bolt (21) rotatably supported inthe bushing (20) and axially spaced apart pegs (23, 24), each peg (23,24) being supported in a respective side guide member (7, 8) and rigidlyjoined with the respective side guide member (7, 8), and furtherincluding a lubricant channel (25) located along the axis (22) of thebolt (21) and having radial bores (26) extending to the outer surface(27) of the bolt (21).
 3. Guide rail and link chain for chain sawaccording to claim 1 with the distinction that each cutting plate (4) isfastened on a support plate (28) and the support plate (28) is fixedlyconnected to a slide element (6).
 4. Guide rail and link chain for chainsaw according to claim 1 with the distinction that the slide rails (3)have coolant channels (13) directed toward the outside, and the outletopenings of the channels (13) are arranged in the area of a central axis(14) of the slide surface (13).
 5. Guide rail and link chain for chainsaw according to claim 1 with the distinction that the slide rails (3)consist of a layer pressed material based on a phenol resin.
 6. Guiderail and link chain for chain saws for the finishing of concrete, stoneand masonry, wherein coolant channels extend through the guide rail, andcutting plates are connected with chain members of the link chain, withthe distinction that the guide rail (1) includes plastic slide rails (3)on both lengthwise sides, the chain (2) includes metal slide elements(6) connected with each other through a link (5) and the cutting plates(4) are located on a side (10) of the slide element (6) opposite fromthe guide rail (1), each of the side guide members (7, 8) overlaps arespective outer side surface (11, 12) of the slide rail (3) and liesagainst the respective outer side surface (11, 12), the link (5)includes a bearing bushing (20) pressed into the slide element (6), abolt (21) rotatably supported in the bushing (20 and axially spacedapart pegs (23, 24), each peg (23, 24) being supported in a respectiveside guide member (7, 8) and rigidly joined with the respective sideguide member (7, 8), and further including a lubricant channel (25)located along the axis (22) of the bolt (21) and having radial bores(26) extending to the outer surface (27) of the bolt (21), the bearingbushing (20) and the bolt (21) having a hardness of 55 to 65 Rockwell Cand the slide element (6) and guide members (7, 8) having a hardness of35 to 48 Rockwell C.
 7. Guide rail and link chain for chain saws for thefinishing of concrete, stone and masonry, wherein coolant channelsextend through the guide rail, and cutting plates are connected withchain members of the link chain, with the distinction that the guiderail (1) includes plastic slide rails (3) on both lengthwise sides, thechain (2) includes metal slide elements (6) connected with each otherthrough a link (5) and the cutting plates (4) are located on a side (10)of the slide element (6) opposite from the guide rail (1), each of theside guide members (7, 8) overlaps a respective outer side surface (11,12) of the slide rail (3) and lies against the respective outer sidesurface (11, 12), the link (5) includes a bearing bushing (20) pressedinto the slide element (6), a bolt (21) rotatably supported in thebushing (20) and axially spaced apart pegs (23, 24), each peg (23, 24)being supported in a respective side guide member (7, 8) and rigidlyjoined with the respective side guide member (7, 8), and furtherincluding a lubricant channel (25) located along the axis (22) of thebolt (21) and having radial bores (26) extending to the outer surface(27) of the bolt (21), the lubricant channels (25, 26) and all theinterspaces of the links being filled with a water-resistant molybdenumgrease.